Ski having concave sides



June 6, 1950 L.. BEERLI sx1 HAVING coNcAvE sInEs Filed oct. 28, 194'?Patented June 6, L1950 -Luuisneer1i,.Engelberg,switzerland. f

npplieseea'ocwberizs, :In Switzerland Nove 'i sains. (creed-1; ist

'Ihesides ofaJskias-fmade today, see'nli-n the vlongitudinal axisthereof, are `inward-ly arched along a curve beginning at theends of therun- 'fninggfa-ceand extending at -a uniform curvature.

The: presentfdayski:-hasagminimunr width lunder the foot-plateyandmaximum widthsfatthe greatest permissibleidistances fromithef-midpointiaswinei or iis-murmuring transversely everslopingPis,'forced:into/'tire snow yunder `'acmanimurn force @at thefpointsaofImaxim-um width, e.atf:the end :,poitioris.` 4113,11; performance .ofswings thus-is -renfdered very -disfiiculu` as; thefmoment 4ofresistance vwhich=-isein--fo1fziiositionI to the swing, increases withtheplengthfo theiski. v

In vorder to decrease the saires'istancafskis have beenfbufilt,theasides-,of whichareprectilinear vor even' arched? outwardly. In. thelattery case Vami: when:oer-iorxnng.'a'swing` yonafharll and snowsurracal emilyl the center portion of the ski grips the latter so 'thatthe ski practically ndsznofresistance. Such a ski may rock on itsoutward arch even on a plane surface, and is no y longer controlled byvthe rider.

`Rectilinear side;.faces also did' not yproveipractical, since-even incase of vslightly rising-snm! surfaces-the skewed ski rocks about itscenter, and is no longer 'sufficiently controllable. s

The-subject matter of my. present inventionisfa skilwhichf overcomes thesaid inconveniencies of theknownskis.

In the ski according to my invention, the sides fore and aft of thebinding tackle each have a point at which the curvature of the sidelines changes its direction. The distance between the said points ofinflexion amounts to 85%, as a maximum, of the length of the runningface measured between the root of the scoop and the rear end of the ski.Forward and rearward of the said points, the side lines are convexlycurved, i. e. deilected inwardly toward the center line of the ski.

The rear point of inflexion preferably is spaced from the rear end ofthe ski by more than of the total length of the ski, or-in otherwordsthe maximum width of the rear portion of the ski is situated at adistance of more than 10% of the ski-length from the rear end of theski.

Portions of the sides between the scoop root and the beginning of theend curvature, preferably are curved outward.

The ski also, could be bent upward, scoop like', at its rear end. Thebeginning of the end-curvature in the latterl case, would have to bereplaced accord Ytstarts-:to .ur efunwardlv.

plaira ty or structural designs are zshown.

fbyway'oiexampiesin the" accompanying drawing, in which y tig.v ,showsAaski 'of zconventiona'lioutlines, in

:rug sidevi'ewferanrstformorinvenuon,

fE Vp planviewfof'fsuchfr'st formja'nd' Y iF-igea e. .eachfshcw'affurthertform of invention:

fia tneeenventienarfskr shown in; nigga are sidesfare "archedlnwardly,itheusualpradiiis o f 'curvature aamountingto 'Z0-@8U metres.. Sucharchtends' .approximately Yfrom; 'the' starting `point aorsther'eareendcurvatureg upwtorthe; root A jof the scoop at the front end portionY otthe ski. TIiheigmaxinrum wfdthfa. ofthe s'kif Yis'at A; e; atthey-point-where Y:th recoup-startetecurve upn u thelipiof h'Scoopbein'g'eloinches The width y,ocl'fhez'slci s-gradually-'decreasedyinthe-dilrect/ion:towrarr1. th idpointf-off. the ski, attains mum-i eateo' te wnereituelinstepef the cot!ijs'lo'cated,1 and is; gradually"increased I teetliewidth@y beat-fthe; rear 'end'` ofthe ski, The

When the skier performs a swing on a hard surface, such conventional skiis no longer positively guided as soon as the radius of the surfaceswell or rise is smaller than the radius R of the ski side arch. When,however, such former radius is greater than R, the ski-which is set onedge during a swinging movement-mainly is supported at A and B, i. e. atthe ends of the effective running face. Points A, B cutharder into thesnow, and the resistance to a swing is increased.

In the first form of invention shown in Figs. 2 and 3, the inwardlyarched portion of the ski sides curved on radius R1, extends only over apart y of the running face between root A of the scoop and point B ofthe rear end curvature. Two outwardly arched portions, curved on aradius R2 and adjoining the central inwardly arched portion, areprovided for. At the transition from the inwardly to the outwardlyarched portions, points of inflexion X and Y are situated. Fore and aftrespectively of the latter points, the sides 11the -Poihtiat which: the'rear` scoop only in depressions which have are outwardly arched. Themaximum widths ai, b1 of the ski are spaced by a distance g which issubstantially shorter than distance e of the conventional ski accordingto Fig. 1. Such points of maximum widths are situated approximately atequal distances from point C of the ski, i. e. at the point of supportfor the skiers instep. The maximum width of the rear portion of the ski,bi, is spaced from the rear end of the ski at a distance which amountsto more than of the length of the ski, and the inward arch extends theend of the ski.

By reason of the fact that the points of maxi-:5" mum width are broughtsubstantially nearer each other than in the conventional ski accordingt6 Fig. 1, the resistance encountered when swinging on a flat surface,is materially decreased,V

Rs of the inward arch is held comparatively small, in order to permit ofpositively guiding the ski also on rather pronounced ground swells.

:The lateral faces of the ski end and the ski front 4portion at the rootof the scoop hug a circular arc of radius R4. The ends of the ski, whenthe latter is set on edge, thus contact` the ground a radius equal to orless than R4. r

In the example shown in Fig. 5, the portions i-which adjoin the inwardarch fore and aitare aligned on a straight line'i which is inclinedrelative to the center line 'of the ski. 'Ihe maximum rear width issituated approximately at the same distance from the ski end as in theexamples 'according to Figs. 3 and 4, but the maximum `front width isset nearer to the root of the scoop and also may be spaced (as in theconventional ski) less than 15% of the ski length from the tip 'of thescoop. Further, the length or chord of the inward arch is less than 280times the rise l? thereof. f

In the example shown in Fig. 6, the sides extend-intermediate of theroot of the scoop and forward point of curve Y-parallel to the center 4line of the ski over a distance n which amounts to at least 10% of thelength of the running surface. The ski rear portion m, situatedntermediate of the ski-end and the rear point of curve X, isrectilinear, and its edge is inclinedrelative to a straight line passingthrough points X and Y-through the same angle a as the edge of theparallel front portion n.

What I claim as new and desire to secure by Letters Patent, is:

1. A ski having inwardly curved sides in which over not more than of thesaid lengths# as measured between the root of the scoop and each lateraledge fore and aft of the bindingtackle comprises points in which theinward curvature ends and changes, the said points being spaced at amaximum of 85% of the length of the running face intermediate of theroot of the scoop and the end of the ski; the parts oi' the said edgesfore of one point and aft of the other point having the same shape andbeing symmetrically arranged with regard to a centre fline which is atright angles to the longitudinal centre line of the ski and passingthrough the longitudinal middle of the curvature.

' I2. A ski according to claim 1, in which the points at which theinward curvature ends are at equal distances from that point of the skion'which the skiers instep is located.

--3. A ski according to claim 1, in which the llateral edges of theskiintermediate of said root and the fore end point of the inwardcurvature Aand intermediate of the end of the ski and the aft end pointof the curvature respectively are rectilinear for a distance whichamountsvto at 'least 10% of the length of said running face and Thefollowing references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 532,954 Germany Feb. 21, 1930804,598 France v Aug. 3, 1936

